The present invention incorporates by reference the eight-stroke internal combustion engine, which was filed as U.S. Pat. No. 6,918,358 (application Ser. No. 10/619,147), and the engine of this type can also be abbreviated as the eight-stroke engine.
The original eight-stroke engine design has two major drawbacks, one is the uneven heat current distribution through the master cylinder wall and the master cylinder head, which reduces the durability of the eight-stroke engine in continuous heavy load operation, the other is the long mixing time required for the high-density-air to mix with the hot-combusting medium in the master cylinder during the injection process, which lowers the fuel efficiency of the eight-stroke engine that operates in high rpm condition. In order to overcome the above-mentioned technical difficulties, the present invention provides an improved configuration of the eight-stroke engine.
The present invention focuses on improving the fuel efficiency of the eight-stroke engine and shorten the mixing time of the high-density-air and the hot-combustion-medium in the master cylinder during the injection-process; as the reduction of the mixing time can directly decrease the heat current through the master cylinder wall, and the two-direction swirling effect can maintain the entire surface area of the master cylinder wall at about the same operating temperature, which results in a low heat loss environment for the cold-expansion-process, thereby achieving an overall fuel efficiency over 35% for the gasoline type eight-stroke engine and 45% for the diesel type eight-stroke engine even in small vehicle application.
In addition, it is also possible to employ an alternating-sparking-sequence with at least more than two spark plugs to enhance the two-direction swirling effect.